Industry News

- September 18, 2020

The forming process of carbon graphite material

There are many forming methods for carbon production. The main methods are compression forming, extrusion forming, vibration forming, and isostatic pressing.

Compression molding

This method uses a vertical press to first make a mold according to the shape and size of the product, and then load a certain amount of kneaded paste or powder into the mold on the worktable of the press, and then start the press to paste Pressure is applied to the material or pressed powder and maintained for a certain period of time to make it shape, and then the pressed compact is ejected from the mold.

The molding method can be divided into one-way pressing and two-way pressing, hot pressing and cold pressing according to different processes and equipment. The molding method is suitable for pressing products with small dimensions in the three directions and the same three-dimensional dimensions, uniform density, and dense structure with high strength, but the products are anisotropic. Mainly used to produce electric carbon products and special graphite products.

Extrusion method

The extrusion method is to use a horizontal extruder, first put the paste into the press chamber, and use the main plunger of the press to apply pressure to the paste. Pre-compression is performed first, and then pressure is applied to make the paste squeeze out through a nozzle with the same cross-sectional shape and size as the product installed in front of the material chamber, and then cut with a cutter according to the required length, which is the extrusion green body .

The extrusion method is suitable for relatively large rods, tubes or other special-shaped products. The extrusion method can be produced continuously, with high production efficiency, simple operation and high degree of mechanization. However, the bulk density and mechanical strength of the product are low, and it is anisotropic. Mainly used in the production of graphitized electrodes, carbon electrodes and carbon blocks.

Vibration forming

Vibration forming is to put the paste into the mold placed on the vibrating table of the vibrating forming machine, and then place a heavy hammer on it, using the high-speed vibration of the vibrating table to make the paste compact and forming.

The vibrating forming machine has a simple structure. As long as a small forming pressure is applied to the paste, it can produce larger size products. It is especially suitable for producing thick and short products and some special-shaped products with the same dimensions in the three directions of length, width and thickness. Such as pre-baked anodes, cathodes, carbon blocks and large or extra large carbon electrodes and crucibles.

Isostatic pressing

Isostatic pressing is done in an isostatic pressure vessel. It fills the compressed powder into an elastic mold made of rubber or plastic, seals it and puts it in a high-pressure vessel, and uses an ultra-high pressure pump to drive high-pressure liquid medium (oil Or water), the pressed powder is pressed and formed. Isostatic pressing has two types: cold isostatic pressing and hot isostatic pressing.

Isostatic pressing can produce isotropic products and heterogeneous products with uniform structure, high density and strength. It is generally used to produce special graphite, especially large-size special graphite products.